#include <stdio.h>

int main(int argc, char *argv[])
{
    char input[100] = {0};
    printf("please input your string:");
    scanf("%s", input);

    char *start = input;
    char *move = input;

    while(*start) {
        start++;
    }

    start--;

    while(move < start) {
        char tmp = *move;
        *move = *start;
        *start = tmp;
        move++;
        start--;
    }

    printf("reverse your input: %s\n", input);

    return 0;
}
